Theses and Dissertations

Permanent URI for this collectionhttps://hdl.handle.net/10217/100404

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Herder observations of pasture and hydro-climatic changes in Mongolia
(Colorado State University. Libraries, 2024) Lilie, Darya, author; Fassnacht, Steven, advisor; Barnard, David, committee member; Swetnam, Sunshine, committee member
Mongolia's climate is extreme and changing with long, cold winters, and dry, hot summers. Mongolia has many sunny days, and precipitation tends to be low. Climate change has altered Mongolian rangelands over the years, from declining water sources and forage production, to shifting boundaries of the ecological zones. With increasing temperatures and extreme precipitation events, climate change is expected to continue to alter rangeland conditions. In addition to climate change, overgrazing contributes to land degradation, leading to desertification in some areas of Mongolia. To combat land degradation community-based rangeland management (CBRM) programs were implemented in some soums (counties) in Mongolia, however they can only be successful if they incorporate the existing institutions that coordinate pastoralist mobility. In this thesis, herder interviews were combined with station and remote sensing data to assess changes in pasture and climate over ecozones in Mongolia, considering the impact of CBRM initiatives. This study focused on interviewing herders from community managed and non-managed soums to use their traditional ecological knowledge (TEK) to assess change. Herder surveys answered both close-ended questions on a 5-point Likert scale about changes observed in climate, snow, rivers, lakes, springs, and rangeland conditions, and open-ended questions on causes, impacts, and adaptations to climate and rangeland conditions across three ecozones (forest steppe, steppe, and desert steppe) for a pair of soums in each ecozone, one with community-based managed and the other without (3 ecozones x 2 soums). Using the different datasets, we compared the remote sending data on rangeland conditions variability and station data on temperature and precipitation variability versus the herder responses to close-ended questions across the ecozone-management pairs, evaluated herder responses from open-ended questions on the causes, impacts, and adaptations to changes in climate and rangeland conditions in comparison to the herder responses to open-ended questions by soum and ecozones, and combined the sensor variability versus the degree of consensus (complete agreement) among herder closed-ended responses to explain herder responses to causes, impacts, and adaptations. Herder observations and remote sensing data were in agreement for changes in the pasture conditions and precipitation. Herder responses and station data were less in agreement for temperature trends, depending on the season. The open-ended questions about causes, impact, and adaptation of pasture change corresponded to the overall climatic and pasture changes observed by station–remote sensing data and from the closed-ended questions. Key reasons for change were rain and water, dzud (Mongolian winter extreme weather), wind, sand, dust, and desertification, and livestock. These heavily impact livestock, quality of life, and money. Adaptation to change were to prepare the livestock better through making and purchasing hay in the north, and more movement to follow vegetation and water in the south.
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Inter-daily temperature variability in the southern Rocky Mountains of Colorado
(Colorado State University. Libraries, 2024) Steen, Brian, author; Fassnacht, Steven, advisor; Barnard, David, committee member; Ronayne, Michael, committee member
While daily temperature variability has decreased in northern latitudes, variability across the western United States has increased. Changes in temperature variability can influence hydrological and earth system processes that could have severe ecological impacts. Mountainous areas are more sensitive to warming trends, but daily temperature variability in the Rocky Mountains is unknown. We investigated daily temperature trends across the Yampa and Rio Grande watersheds of the Southern Rocky Mountains in Colorado using 23 Snow Telemetry (SNOTEL) stations at high elevation, snow-covered regions (2521-3536m) and ten Cooperative Observer Program (COOP) stations at lower elevations (1961-2840m). SNOTEL data were homogenized to account for temperature sensor changes in 2003-2006, with five possible bias correction combinations compared. Daily data were detrended using the long-term and annual means, so that the day-to-day variability could be quantified. Trends were analyzed from the mid-1980s to 2022 using the Mann‐Kendall significance test and Theil‐Sen's rate of change. Inter-daily temperature variability (ITV) changed over the 30+ year period of evaluation with mixed increases and decreases based on location and time period. Variability in the spring at 26 stations has increased upwards of 0.8°C per 30 years in the spring. Ninety percent of stations have increased in variability up to 1.0°C per 30 years in the fall. In the summer, Yampa area stations decreased in variability while the Rio Grande area stations increased, both significantly. Low elevation COOP stations demonstrated smaller increases in variability than high elevation SNOTEL stations in the Rio Grande watershed throughout all seasons. The Yampa watershed showed no similar elevational patterns, but rather decreased variability for SNOTEL stations with little change for variability for COOP stations. The scattered decreases in the Yampa area and at lower elevations emphasize the spatiotemporal variability of montane climatology and suggest increased ITV trends across the Rocky Mountain West are watershed and station specific.

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Browsing Theses and Dissertations by Author "Barnard, David, committee member"